It is a well known technique to add a phenolic compound to a chemically amplified resist as described in Patent Document 1 (JP-A-7-181680 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”)). However, the technique is regarded as subsidiary means for dissolving a resist film in a developing solution. Transmittance of the phenolic compound at 193 nm is low, and thus it is ordinarily not preferred to add the phenolic compound to a resist for an ArF eximer laser (193 nm) because transparency of the resist is remarkably reduced.
In Patent Document 2 (JP-A-2000-241979), a technique of adding a polyhydric phenol to an ArF resist is described. However, since the polyhydric phenol is ordinarily apt to be oxidized, it is insufficient in view of preservation stability. Further, in Patent Document 3 (JP-A-2003-322963), a technique of adding a phenolic compound to an alicyclic resin is described. In the patent document, it is suggested that functions of the phenolic compound are increase in an acid generating efficiency of a photo-acid generator and profile control due to absorption. However, in a thin film having a resist thickness of 250 nm or less, the phenolic compound specifically described therein is insufficient in view of improvements in the profile control and line edge roughness.
With miniaturization of resist pattern, the resist thickness tends to decrease 250 nm or less. However, when the resist thickness is simply decreased, pattern collapse and degradations of profile, line edge roughness, exposure latitude (tolerance of variation in an exposure amount at the exposure), focus latitude (tolerance of misalignment of focus at the exposure), or the like are observed. Thus, a resist adapting to a thickness of 250 nm or less has been desired.
Patent Document 1: JP-A-7-181680
Patent Document 2: JP-A-2000-241979
Patent Document 3: JP-A-2003-322963